python 6 lines · 1 tab

Certificate transparency checks for unexpected certificate issuance

Kai Nakamura Apr 2026
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import requests

response = requests.get('https://crt.sh/', params={'q': '%.example.com', 'output': 'json'}, timeout=15)
response.raise_for_status()
certs = response.json()
print(certs[:5])
1 file · python Explain with highlit

Certificate transparency monitoring is cheap detection for a surprisingly important risk. If a certificate appears for a domain you own and you did not expect it, that deserves immediate investigation. I like monitoring this externally so it still works during internal outages.

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